I think Lee Joon Gi pulls off hands down the best action sequences of all kdramas. Pair that with an epic plot line and the most powerful villain character and acting and you have what is called "Again my life" . It pulled me in at the first few episodes itself and somehow well connected all logical loop holes. You know you will be satisfied with action and plot watching this one as there was no bullshit about worrying about altering the future or intervening and all that crap. All most felt like I was watching an Isekai Anime too where the hero has all the cheat codes he can use to bring down the biggest nemesis of all time.